Improved spring- burglar-alarm for doors



ilahritntl Sttte' 'intent bllllr" Letters Patent No. 90,575, met Mayet, 1869.

IMPROvED SPRING- BU'RGLAR-ALARM FOR DOORS.

The Schedule referred to in these Letters Patent and making part of the same.

To all 'whom fit may concern:

Be it 'known that I, GEORGE W. R. PoLLooK, of Y Boston, in the county of Suffolk, and State of Massachusetl's, have invented a Combined Door-Spring and Alarm; .and I do hereby declare that the following, taken in connection with the drawings which accompany and form part of this specification, is a descrip tion of my invention, sufficient to 'enable those skilled .in the art to practise it.

In this invention, I so combine `a door-spring with analarm, or noise-giving apparatus, that movement .11, a pulleyc, to which is attached a cord, d, by one end, the cord being coiled around the pulley, and having its other end projecting through the casing n, so that said projecting end may be attached either to the door or to the door-frame, or some part adjacent therekto, according as the casing c is fixed to the door or to the door-frame. A-

In the casing the helical spring f is xed by one end thereto, and by the other-end to the p nlley c, so that when, by opening the door, with which the stringlis connected, it is caused to unwind, and turn the pulley, it does so against the resistance oi' spring f, which is thereby coiled more closely, or is wound up. On the .pulley c is fixed the star-wheel g, so that it rotates with the pulley, and tothe case a is riveted the spring h., so that its free end enters between the projections of the star-wheel, which, when the Wheel is made to revolve, strike against and vibrate the spring in the 'manner of a watchmans rattle, producing a similar noise and this is effected whether the starwheel is rotated in one or the other directionpso that it will be obvious that the alarm will be sounded-both in the opening 'and the closing of a door to which itis attached.

I claim the combined door-spring and alarm, constructed and arranged as described, so as to close the door with which it may be connected, and to sound an alarm both in the opening and in the closing of the door.

Witnesses: GEORGE WV. R. POLLOCK.

J. B. CROSBY, L. H. LATIMER. 

